Segment and Related Information - Summary (Detail) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($) segment	Sep. 30, 2024 USD ($)
Segment Reporting
Number of reportable segments | segment			5
Net operating revenue royalty (as a percent)	15.00%		15.00%
Royalty amount	$ 17	$ 13	$ 48	$ 34
Operating revenues	6,443	5,609	18,891	16,170
Operating expenses	3,833	3,399	11,319	9,830
Selling, general and administrative	665	525	2,048	1,517
Other net expenses	227	8	278	64
Depreciation, depletion and amortization	729	558	2,093	1,615
Income from operations	989	1,119	3,153	3,144
Capital expenditures	847	889	2,303	2,218
Collection and Disposal [Member]
Segment Reporting
Operating revenues	5,321	5,084	15,524	14,722
Other net expenses	46	(17)	72	(17)
Depreciation, depletion and amortization	528	491	1,522	1,416
Income from operations	1,468	1,426	4,274	4,064
Capital expenditures	631	628	1,774	1,491
Collection and Disposal [Member] | East Tier [Member]
Segment Reporting
Operating revenues	2,336	2,242	6,768	6,501
Other net expenses	46	2	54	4
Depreciation, depletion and amortization	287	263	810	757
Income from operations	740	718	2,130	2,064
Capital expenditures	348	305	905	726
Collection and Disposal [Member] | West Tier [Member]
Segment Reporting
Operating revenues	2,228	2,138	6,561	6,207
Other net expenses		(19)	2	(19)
Depreciation, depletion and amortization	234	221	692	639
Income from operations	728	708	2,164	2,009
Capital expenditures	271	306	828	725
Collection and Disposal [Member] | Other Ancillary [Member]
Segment Reporting
Operating revenues	757	704	2,195	2,014
Other net expenses			16	(2)
Depreciation, depletion and amortization	7	7	20	20
Income from operations			(20)	(9)
Capital expenditures	12	17	41	40
Recycling Processing and Sales [Member]
Segment Reporting
Operating revenues	372	432	1,137	1,205
Other net expenses	155	(1)	161	(1)
Depreciation, depletion and amortization	47	33	131	93
Income from operations	(137)	21	(95)	69
Capital expenditures	59	124	167	351
WM Renewable Energy [Member]
Segment Reporting
Operating revenues	115	87	321	225
Other net expenses	11	7	11	7
Depreciation, depletion and amortization	16	9	46	26
Income from operations	21	28	78	67
Capital expenditures	114	147	351	361
WM Healthcare Solutions [Member]
Segment Reporting
Operating revenues	628		1,893
Other net expenses	9		27
Depreciation, depletion and amortization	110		316
Income from operations	(21)		(65)
Capital expenditures	42		122
Corporate and Other [Member]
Segment Reporting
Operating revenues	7	6	16	18
Other net expenses	6	19	7	75
Depreciation, depletion and amortization	28	25	78	80
Income from operations	(342)	(356)	(1,039)	(1,056)
Capital expenditures	1	(10)	(111)	15
Operating Segments [Member]
Segment Reporting
Operating revenues	7,908	6,840	23,122	19,741
Operating expenses	5,293	4,625	15,533	13,386
Selling, general and administrative	670	530	2,065	1,532
Operating Segments [Member] | Collection and Disposal [Member]
Segment Reporting
Operating revenues	6,570	6,238	19,124	18,063
Operating expenses	4,324	4,118	12,646	11,961
Selling, general and administrative	204	220	610	639
Operating Segments [Member] | Collection and Disposal [Member] | Processing fees [Member]
Segment Reporting
Income from operations	(19)	(29)	(59)	(77)
Operating Segments [Member] | Collection and Disposal [Member] | East Tier [Member]
Segment Reporting
Operating revenues	2,974	2,826	8,594	8,178
Operating expenses	1,813	1,747	5,336	5,079
Selling, general and administrative	88	96	264	274
Operating Segments [Member] | Collection and Disposal [Member] | West Tier [Member]
Segment Reporting
Operating revenues	2,788	2,662	8,181	7,736
Operating expenses	1,738	1,657	5,066	4,829
Selling, general and administrative	88	95	257	278
Operating Segments [Member] | Collection and Disposal [Member] | Other Ancillary [Member]
Segment Reporting
Operating revenues	808	750	2,349	2,149
Operating expenses	773	714	2,244	2,053
Selling, general and administrative	28	29	89	87
Operating Segments [Member] | Recycling Processing and Sales [Member]
Segment Reporting
Operating revenues	470	503	1,417	1,414
Operating expenses	389	434	1,175	1,207
Selling, general and administrative	16	16	45	46
Operating Segments [Member] | WM Renewable Energy [Member]
Segment Reporting
Operating revenues	116	88	323	228
Operating expenses	63	41	177	120
Selling, general and administrative	5	3	11	8
Operating Segments [Member] | WM Healthcare Solutions [Member]
Segment Reporting
Operating revenues	738		2,219
Operating expenses	511		1,507
Selling, general and administrative	129		434
Operating Segments [Member] | Corporate and Other [Member]
Segment Reporting
Operating revenues	14	11	39	36
Operating expenses	6	32	28	98
Selling, general and administrative	316	291	965	839
Intercompany Elimination [Member]
Segment Reporting
Operating revenues	1,465	1,231	4,231	3,571
Operating expenses	1,460	1,226	4,214	3,556
Selling, general and administrative	(5)	(5)	(17)	(15)
Intercompany Elimination [Member] | Collection and Disposal [Member]
Segment Reporting
Operating revenues	1,249	1,154	3,600	3,341
Intercompany Elimination [Member] | Collection and Disposal [Member] | East Tier [Member]
Segment Reporting
Operating revenues	638	584	1,826	1,677
Intercompany Elimination [Member] | Collection and Disposal [Member] | West Tier [Member]
Segment Reporting
Operating revenues	560	524	1,620	1,529
Intercompany Elimination [Member] | Collection and Disposal [Member] | Other Ancillary [Member]
Segment Reporting
Operating revenues	51	46	154	135
Intercompany Elimination [Member] | Recycling Processing and Sales [Member]
Segment Reporting
Operating revenues	98	71	280	209
Intercompany Elimination [Member] | WM Renewable Energy [Member]
Segment Reporting
Operating revenues	1	1	2	3
Intercompany Elimination [Member] | WM Healthcare Solutions [Member]
Segment Reporting
Operating revenues	110		326
Operating expenses	16		36
Income from operations	108		315
Intercompany Elimination [Member] | Corporate and Other [Member]
Segment Reporting
Operating revenues	$ 7	$ 5	$ 23	$ 18